1. Field of the Invention
The present invention relates to weapon sights, and more particularly to an improved modular weapon aiming system having both day and night aiming capability.
2. Description of Related Art
Military and law enforcement personnel who use weapons, such as handguns and rifles, have long sought ways to improve their aim. By improving their shooting accuracy, an operator increases his own effectiveness and chance of survival, while minimizing the possibility of innocent bystanders being shot.
Virtually every handgun and rifle comes equipped with a mechanical bore sight. The typical bore sight comprises a first upstanding member at the far end of the barrel and a second upstanding member at the close end of the barrel. The two members are of equivalent height. To use the bore sight, the operator visually sights down the length of the barrel of the gun, aligning the tops of the two members with the desired target. Usually, one or both of the members are laterally and vertically adjustable, so that the sight can be accurately calibrated for the particular operator.
It is also typical for operators of weapons to use the mechanical bore sight in conjunction with an optical scope. The scope would be mounted onto the upper surface of the weapon between the bore sight and the operator, and is usually equipped with magnification, such as three times magnification (3.times.). The operator can see the bore sight through the scope, as well as the distant target. This combination of bore sight and scope enables the operator to accurately aim at and strike these distant targets. However, it should be apparent that this sighting method is only operable in daylight conditions.
Modern technology has enabled great advances in weapon sighting. Most notably, the use of lasers has resulted in great improvements in sighting accuracy. A laser sight for a weapon comprises a low intensity laser which is mounted on top of the weapon. When the laser is activated, it points in the direction parallel to the barrel of the weapon. The spot of light formed by the laser provides a reticle for the operator to aim with. The operator simply shines the laser spot on the desired target. By seeing the laser spot on the desired target, the operator has instant feedback information assuring that the weapon is accurately aimed. The use of laser sighting systems can enable even relatively inexperienced operators to accurately hit their desired targets.
A significant drawback with laser sighting systems is that the laser light is also visible to observers, which can trace the source of the laser light back to the operator. This would effectively give away the location of the operator, putting him at risk to retaliation by hostile forces. This problem is compounded at night, when hostile forces are utilizing night vision systems which can see the infra-red light beam generated by the laser sight.
To solve this problem, passive sighting systems were developed. An improved passive sighting system utilizes a red-light source, such as a light emitting diode (LED), mounted at a point at the near end of the weapon barrel, and a combining mirror placed further down the length of the barrel and facing the LED. The mirror has a coating which reflects red light yet allows all other frequencies of light to pass through. The red light formed by the LED is reflected in the mirror, and is collimated in a direction parallel to the gun barrel and toward the operator, forming a virtual image of the red LED at an infinite distance aligned with the barrel. The virtual image provides a reticle for the operator which cannot be seen by others. The operator looks through the mirror, seeing the distant target and the virtual image of the red LED suspended at the sight point of the weapon. To aim the weapon, the operator centers the virtual image on the desired target. As with earlier systems, the position of the mirror can be adjusted to calibrate for alignment with the barrel, and for the specific operator This passive red dot aiming system enables the operator to accurately strike his target, without illuminating the target or broadcasting his position.
A problem with this type of passive system, is that it is only effective during daylight conditions. At night, the operator would be unable to see the distant target, although the red light would continue to be visible. To remedy this problem, night vision systems are utilized. A night vision system intensifies the ambient light to produce an image. These systems require some residual light, such as moon or starlight, in which to operate. The ambient light is intensified by the night vision system to produce an output image which is visible to the human eye. The present generation of night vision systems utilize image intensification technologies to intensify the low level of visible ambient light and also make visible the light from the infra-red (IR) spectrum. The image intensification process involves conversion of the received ambient light into electron patterns and projection of the electron patterns on a phosphor screen for conversion of the electron patterns into light visible to the observer. This visible light is then viewed by the operator through a lens provided in the eyepiece of the system.
Night vision systems can be either mounted to the weapon itself, or can be worn by the operator as a goggle in either a face mask mounted or helmet mounted configuration. When mounted to the weapon, the night vision systems typically use 3.times. magnification as in the day light optical scopes. In contrast, night vision systems used as a goggle do not use 3.times. magnification, but instead remain at one times (1.times.) magnification, otherwise it would be difficult for the operator to function.
Night vision systems combined in a single optical scope with a passive red dot aiming system providing an internal reticle have been developed to provide an operator with accurate aiming capability at night or in conditions of darkness. However, the operator is unable to use the same system during the day. Operation of a night vision system during daylight would quickly cause damage to the internal image intensification tube. Thus the operator would have to remove the combined night vision red dot aiming system from the weapon and replace it with a red dot aiming system for use during daylight hours. Each time the aiming device is changed it would have to be recalibrated or re-aligned for the weapon and for the operator. In addition, the operator would have to carry both a daytime red dot aiming system, and a combined night vision scope/red dot aiming system for use at night. Since most law enforcement and military forces operating at night already utilize either face mask mounted or helmet mounted night vision systems, as described above, the use of a combined night vision scope/red dot aiming system would be redundant.
Combination scopes having night vision capability and red dot aiming systems which are switchable between day and night use are available in the prior art. These combination devices utilize a plurality of internal hinged mirrors to allow the observed image and reticle dot to bypass the image intensification tube during daytime usage. The operator can reconfigure the mirrors to direct the ambient light into the image intensification tube when desired. While this combined scope enables the operator to use the red dot aiming system in both daylight and night conditions, it adds considerable weight, bulk and complexity to the weapon. This is especially apparent during daytime, when the additional weight of the night scope portion is not in use. A further problem with this combination is that the plurality of moving mirrors can easily fall out of alignment, rendering the device useless.
Thus, it would be desirable to provide a modular, day/night aiming system which combines the red dot aiming system with a night vision system. It would be further desirable to provide a modular, day/night aiming system which combines a red dot aiming system with a night vision system that can be switched between day usage and night usage without requiring recalibration of the red dot aiming system. It would be further desirable to provide a modular, day/night aiming system which combines a red dot aiming system with a night vision system in which the night vision system could be simply removed from the combination for usage during the day. It would be further desirable to provide a modular, day/night aiming system which combines a red dot aiming system with a helmet mounted or face mask mounted night vision system.